Always consult the Owners Manuals
From Axe-Fx II Wiki
What is re-amping
Re-amping is the process of recording a dry signal to be "processed" at a later time. This lets you experiment with different amp models, before deciding which one will be used on the final track.
The Axe-Fx is designed for easy re-amping. The AX8 can do it too but it takes more effort.
Re-amping with the Axe-Fx III
Re-amping is covered in section 3 of the Owner's Manual.
Re-amping with the Axe-Fx II
The USB output signal of the Axe-Fx always contains 4 signals: 4 x mono / 2x2 stereo. There's nothing you have to set up in the Axe-Fx. Channels 3 and 4 contain the raw data from the instrument input, without processing by the Axe-Fx. You record this on the computer by selecting input signals 3 and 4 as sources. This is known as the DI track.
Play this recording from the software back into the Axe-Fx, by setting the software's output source to Axe-Fx II, and selecting USB (or Digital) as input source in the Axe-Fx's I/O menu. Then tweak the signal on the Axe-Fx II by creating an empty preset and adding effect blocks, such as Amp and Cab. When you are happy with the result, record channels 1 and 2 again which contain the re-amped audio.
To record audio on the computer through USB, USB/Digi Out Source in I/O menu should be set to Output 1. If you want to route the guitar's dry input signal directly to the output (USB or digital), set USB/Digi Out Source to Input. To send dry signal only from the Axe-Fx II to the DAW through Output 2, set Echo Output 2 to Input.
The DI signal level of channels 3 and 4 is fixed, for good reason. When you send that signal back into the Axe-Fx, it has the same level as the original signal sent to the grid. This means you don't have to adjust anything when re-amping. You simply send the signal back. source
"You are getting a bit-copy of the signal out of your guitar. Do not adjust the level. It may sound quiet because your guitar IS quiet when not amplified. When you put that signal back into the Axe-Fx it will be gained up and sound just like when you are playing through the Axe-Fx." source
Make sure to use the correct Input Mode when re-amping. For example, using Stereo instead of Left Only will attenuate the incoming signal.
- Bernd Kiltz.
- Using Cubase.
- Shasha's guide to re-amping.
- GotMetalBoy's tutorial on re-amping via Spdif with a Focusrite Scarlett 6i6.
- Neokrunchers all digital method for best signal quality.
Re-amp with the AX8
To send out a DI-signal, adjust the routing in the grid to create a dry DI-signal. Then use the FXL block to send that signal through Output 2 to the computer. Then send the recorded DI-signal back into the AX8 again using Input 2 (analog), process it on the grid, and record it using S/PDIF OUT or the analog outputs.
Another way to send out a dry signal through Output 2, is to set Echo Output 2 to "Input 1" in I/O.